Carton squaring method and mechanism



Oct. 30, 1962 R. K. GALLOWAY 3,060,651

CARTON SQUARING METHOD AND MECHANISM Filed March 3, 1959 4 Sheets-Sheet 1 INVEN'I'OR ROBERT K. GALLOVIAY ATTORNEY Oct. 30, 1962 Filed March 3, 1959 R. K. GALLOWAY CARTON SQUARING METHOD AND MECHANISM 4 Sheets-Sheet 2 1962 R. K. GALLOWAY 3,060,651

CARTON SQUARING METHOD AND MECHANISM Filed March 3, 1959 4 Sheets-Sheet 3 INVENTOR ROBERT K.GALLOWAY ATTORNEY Oct. 30, 1962 R. K. GALLOWAY 3,060,651

CARTON SQUARING METHOD AND MECHANISM Filed March 3, 1959 4 Sheets-Sheet 4 ROBERT K. GALLOWAY s2 BY ATTORNEY a 8 INVENTOR United States Patent Ofitice 3,060,651 Patented Oct. 30, 1962 3,060,651 CARTON SQUARING METHOD AND MECHANISM Robert K. Galloway, Hoopeston, Ill., assignor to FMC Corporation, a corporation of Delaware Filed Mar. 3, 1959, Ser. No. 796,967 21 Claims. (Cl. 53-14) This invention relates to packaging machines, and particularly to a method of and mechanism for squaring cartons after articles have been inserted therein and the carton ends closed.

This application is a continuation-in-part of a parent application filed February 24, 1959, by Robert K. Gal loway, Serial Number 794,871, now abandoned, and en' titled Carton Squaring Method and Mechanism.

One of the difiiculties encountered in the packaging industry arises from the tendency of the carton end flaps of a filled and closed car-ton to spring back toward their open positions due to the inherent resiliency of the carton material. Cartons of various types rely upon reception of a locking tab on one end flap within a slot in an opposed end flap to hold the flaps closed. The tendency of the flaps of such cartons to spring back toward their open positions usually causes the flaps to assume an outwardly curved or arcuate conformation, leaving gaps at the ends of the closed flaps and along the distal edge of the outermost, or overlying flap. This is not only unsightly but it is also objectionable for the reason that it seriously impairs the compressive strength of the carton, i.e., the ability of the carton to resist crushing when several filled and closed cartons are piled on top of each other as is usually necessary for storage, shipment, or other handling of the filled cartons in shipping containers. Moreover, the tendency for a carton to gap open at one or :both of its ends seriously reduces the ability of the carton to protect its contents not only from crushing because of the cartons reduced compressive strength but also from the standpoint of sanitation and preservation of the moisture content of the commodity within the carton.

These disadvantages inherent in cartons of the locking tab and slot type create such serious problems that it has become common practice to individually overwrap the cartons after they have been filled and closed. This, of course, entails considerable extra expense not only because of the cost of the overwr-apping material itself but also because of the cost of the overwrapping machinery and the extra handling involved.

It is, therefore, an object of the present invention to provide an improved method of squaring car-tons.

Another object is to provide mechanism for performing the carton squaring method of the invention.

Another object is to provide an improved carton squaring mechanism which is adapted for, but which is not necessarily limited to, use in conjunction With automatic machinery for filling and closing cartons in rapid succession.

Another objection is to provide an improved mechanism for completing the operation of closing a carton in a manner that avoids the necessity of overwrapping.

Another object of the invention is to provide a carton squaring mechanism which zcrimps the corners of the carton in a manner that overcomes the inherent tendency of the closed carton flaps to return to their open positions.

Another object of the invention is to provide a carton squaring mechanism which minimizes friction between the carton and the squaring mechanism.

These and other objects and advantages will become apparent from the following description and accompanying drawings, in which:

FIG. 1 is a perspective of a carton closing device incorporating the squaring mechanism of the present invention.

FIG. 2 is an enlarged perspective of one of the carton squaring shoes constituting a part of the mechanism illustrated in FIG. 1.

FIG. 3 is an end elevation of the carton squaring shoe of FIG. 2, drawn to a larger scale.

FIG. 4 is a side elevation of the squaring shoe of FIG. 3.

FIG. 5 is an end elevation illustrating a modified form of carton squaring shoe of the invention.

FIG. 6 is a fragmentary perspective illustrating another modification of carton squaring mechanism of the invention.

FIG. 7 is an end elevation of one of the carton squaring shoes illustrated in FIG. 6.

FIG. 8 is a fragmentary perspective of a carton of the type that is adapted to be squared up by the structure described herein in performing the method of the invention.

FIG. 9 is a fragmentary perspective illustrating the gapping tendencies of a carton closed and squared lby previously known carton closing machinery.

FIG. 10 is a section taken on line 10'10 of FIG. 9.

FIG. 11 is a fragmentary perspective of a carton squared by a mechanism of the present invention.

FIG. 12 is a section taken on line 1212 of FIG. 11.

The carton squaring mechanism of the present invention is an improvement over that disclosed and described in my copending application, Serial No. 757,596, filed August 27, 1958, now US. Patent No. 2,979,876, and entitled Carton Closing Mechanism, and reference is made thereto for the details of construction which are common to both mechanisms.

Referring now tothe drawings and particularly FIG. 1 thereof, cartons to be closed and squared are carried by a conveyor 20. The cartons rest on the upper surface of the conveyor 20 and are confined between spaced pusher blocks 22 so that the cartons are successively propelled between two flap folding mechanisms '23 and 24 which fold and interlock the upper and lower end flaps of the cartons with a continuously advancing, or progressive, type of action in the manner described in the above mentioned copending application, Serial Number 757,596. After having thus been closed, each carton is similarly propelled through a carton squaring mechanism 25 of the present invention without interrupting progress of the carton on the conveyor 20.

One of the cartons C to be closed and thereafter to be squared by mechanism 25 of the present invention is illustrated in FIG. 8 and comprises a top panel 28, a bottom panel 30, a front panel 32, and a rear panel 33. Front and rear end flaps 34 and 36 are attached respectively to the front and rear panels and project outwardly therefrom. These end flaps are tucked inwardly by suitable mechanism (not shown) prior to the arrival of the carton between the folding mechanisms 23 and 24 (FIG. 1) which fold the top and bottom end flaps 38 and 40 attached to the top and bottom panels 28 and 30, respectively. As the carton C progresses through the folding mechanisms 23 and 24 the bottom flap 40 is folded upwardly and the top flap 38 is folded downwardly thereover. As this occurs, locking tabs 42 that project from the upper flap 38 are inserted through slits 44 provided in the lower flap 40.

If nothing further is done to the carton, the end flaps will tend to bow outwardly due to the inherent resilience of the carton material. As a consequence, the carton end, instead of being properly closed, will present a small gap 48 (FIG. 9) at each end of the overlapping flaps 38 and 40 and a large gap 50 (FIG. 10) along the distal edge of the outer flap 38. The gapping of the carton causes the finished carton to have an unsightly appearance if no overwrap is used, and necessitates overwrapping if an air-tight closure of the carton is to be achieved. Furthermore, the failure of the flaps 38 and 40 to lie flat against each other in planes perpendicular to the top and bottom panels 28 and 30 seriously lessens the resistance that the carton can offer to forces tending to crush the carton.

The squaring mechanism 25 of the present invention comprises a pair of squaring shoes 60 and 62 (FIG. 1) attached to the terminal ends of the flap folding mechanisms 23 and 24, respectively, in position for the ends of each carton to engage and pass through the respective shoes 60 and 62 immediately after having been closed. Since the squaring shoes 60 and 62 are similar to each other, though oppositely disposed, only the shoe 62 will be described in detail. The shoe 62 (FIGS. 14) is of channel-shaped cross section comprising a body portion or web 64 having an inwardly facing vertical face 65, and upper and lower flanges 66 and 68, respectively, which project inward from the face 65 in perpendicular relation therewith. The opening between the flanges 66 and 68 corresponds closely to the height of the finished carton, with the result that when a carton is propelled sideways with one end wall in sliding engagement with the outer face of the overlying end flap 38, the end region of the top and bottom panels 28 and 30 engage the lower face of the upper flange 66 and the upper face of the lower flange 68, respectively, in a manner that creases, or breaks the carton material along the hinge lines of the flaps 38 and 40. This tends to set the end flaps in position at right angles with the top and bottom panels 28 and 30, respectively, and thereby to square up the end of the closed carton.

The vertical face 65 of the web 64 is relieved by a plurality of horizontally extending grooves 70 to reduce the surface contact between the shoe and the cartons and thus reduce friction therebetween. A horizontal crimping groove 72 open at both ends, extends longitudinally of the shoe 62 in the face 65 at the juncture between the vertical face 65 and the lower surface of the upper flange 66. A similar crimping groove 74 is provided at the juncture between the vertical face 65 and the upper surface of the lower flange 68. The crimping grooves 72 and 74 are quite narrow, the width of each crimping groove being substantially equal to twice the thickness of the carton stock.

A thermostatically controlled heater element 80 (FIG. 1) is attached to each shoe 60 and 62 and is connected to a suitable source of electrical energy (not shown). The heaters keep the squaring shoes hot to relieve the strains in the material of a carton engaged by the shoes and help set the material so that the flaps 38 and 40 will retain their proper folded positions. The temperature to which the shoes are heated will depend upon the material of the cartons and the speed at which the cartons are to be passed therethrough. The faster the cartons are processed, the less time they are in contact with the shoes, which will necessitate maintaining the shoes at a higher temperature. By way of example, with a line speed of one hundred fifty cartons per minute when handling cardboard cartons the temperature of the shoe should be approximately 250, and for the same cartons advanced at a line speed of two hundred cartons per minute the temperature of the shoes should be approximately 300. Of course, the temperature must be kept low enough to avoid scorching the cartons, or if printed or coated cartons are being run, low enough to avoid causing the coating to melt and/ or smear.

The two shoes 60 and 62 are so spaced apart that the bottoms of the grooves 72 and.74 in the shoe 60 are spaced from the bottoms of the corresponding grooves in the shoe 62 a distance substantially equal to the length of the top and bottom panels 28 and 30, respectively, i.e., the dimension of the carton C measured between the walls thereof that are formed when both sets of flaps 38 and 40 are closed. Thus, the distance between the faces 65 of the webs 64 of the opposed shoes 60 and 62 (Le, the surfaces in which the grooves 72 and 74 are formed) is actually less than the overall length of the carton C. Consequently, when a carton C is pushed into and through the space between the two shoes 60 and 62, the faces 65 of the webs 64 apply pressure to the outer surfaces of the flaps 38 and 40 at both ends of the carton. In this manner, the walls of the carton C that are formed by the closed end flaps 38 and 48 are flexed inward, causing each to assume a concave configuration, while some of the carton material adjacent the crease lines joining the top panel 28 with the upper flaps 38 is forced into the grooves 72 and some of the material adjacent the crease lines joining the bottom panel 30 with the lower flaps 40 is forced into the grooves 74 forming reverse folds, or beads 81 and 82, respectively (FIGS. 11 and 12), along the upper and lower edges of both ends of the carton. The edge between the lower wall of each groove 72 and the associated surface 65 causes a reverse crease line 83 (FIG. 12) to be formed in the flap 38 engaged thereby (FIGS. 11 and 12), and the edge between the upper wall of each groove 74 and the associated surface 65 causes a similar crease line 84 to be formed in the respective flap 40.

Whereas the application of heat may not always be necessary, it has been found that under certain circumstances, as, for example, when cartons of a particular type are being processed, heating the carton stock, at the time that it is being shaped by the shoes, or immediately thereafter, relieves the strains created therein by the folding of the flaps to their closed relation and by the formation of the beads 81 and 82 and the crease lines 83 and 84, thus setting the carton stock. This setting of the carton stock is an important factor in enabling the carton to retain the configuration imparted thereto by the squaring shoes.

When the carton C leaves the shoes 60 and 62 each of its ends will have a very neat, slightly channelled appearance as illustrated in FIGS. 11 and 12 and there will be no tendency of the ends flaps 38 and 40 to swing open and thus to form gaps. A carton which has been squared in this manner not only is neater in appearance but is much stronger and offers a much greater resistance to crushing when the cartons are stacked one on top of the other. The reason for this is that a concave configuration is imparted to each closed end of the carton, with the result that if the top and bottom panels 28 and 30 are subjected to forces tending to crush the carton in the region adjacent one of its ends, the flaps 38 and 40 will be urged inward, rather than outward as they would be if the carton end were convex, as in the case of the carton shown in FIGS. 9 and 10.

Furthermore, since the flaps 38 and 40 lie fiat against each other in surface contact throughout a considerable extent of their respective contiguous surfaces, the carton is almost, if not quite, hermetically sealed, and thus placed in a condition wherein it provides eflicient protection for its contents, both against contamination and against variation of moisture content. For this reason, the squaring mechanism of the invention is particularly adapted for use in packaging articles or material in cartons having a surface coating that makes them so impervious to moisture penetration that they provide maximum protection for their contents without overwrapping.

The modified squaring shoe 60a illustrated in FIG. 5 is similar to that shown in FIGS. 1-4 and the portions thereof which are the same as corresponding parts of the shoe 60 have been given the same reference numerals with the suffix a appended thereto. The only difference between the two shoes 60 and 60a is that the grooves 72 and 74 in shoe 60 have been replaced by outwardly sloping beveled surfaces and 132, respectively.

In the use of these shoes the distinct channelling of the carton ends is not effected. However, the end flaps 38 and 40 at each end of the cartons C are bent inwardly beyond the vertical so that a concave configuration of substantially uniform curvature is imparted to the carton end. Thus when pressure is applied to the panels 28 and 30 of the carton, the flaps 38 and 40 will tend to turn inward, as in the case of a carton end squared by the shoes 60 and 62 and will not gap open.

The modification illustrated in FIGS. 6 and 7 likewise employs two opposed squaring shoes 60b and 62b attached to the terminal ends of the two folding mechanisms 23 and 24, respectively. Instead of being formed with shallow grooves in its inwardly facing surface, the body portions 64b of each shoe 60b and 62b is cut all the way through to provide three spaced slots 140, 14-2 and 144, respectively.

A vertical shaft 146 extends through the body portion 64b and is held therein by two collars 148 and 150, one above and one below the shoe 60b. The collars 148 and 150 are held in place on the shaft 146 by suitable set screws 152 and 154, respectively. Three rollers 160. 162 and 164 are rotatably mounted on the shaft 146 and within the three slots 140, 142 and 144, respectively, being so dimensioned that they are adapted to turn freely with respect to the shoe 60b. The uppermost roller 160' has an upwardly and outwardly beveled peripheral surface providing a creasing edge 166 at its upper end spaced from the carton engaging surface 155 of the upper flange 66b of the shoe 6012 a distance substantially equal to twice the thickness of the carton stock. The creasing edge 166 projects slightly beyond the inwardly facing vertical face 65b of the shoe 60b. Similarly, the lowermost roller 164 is flared downwardly and outwardly to provide a creasing edge 168 which projects beyond the vertical face 65b and is spaced above the level of the carton engaging surface 156 of the lower flange 68b 2. distance substantially equal to twice the thickness of the carton stock. The central roller 162 is of slightly larger diameter than the other rollers 160 and 164 so that it will contact the end flaps 38 and 4 0 midway between the top and bottom panels of the cartons C as they move therepast and bow said flaps inwardly in the manner indicated by broken lines in FIG. 7.

The opposite squaring shoe 62b is formed similarly to the above described shoe 60b, and is similarly provided with three grooving and forming rollers two of which are shown in FIG. 6, so that it operates in the same manner upon the opposite end of the carton.

The use of this modification produces a finished carton closely resembling, if not, in fact, the same as that which is produced when using the modification illustrated in FIGS. 1-4. The carton material is forced into the spaces between the ends of the rollers 160, 164 and the carton engaging surfaces 155, 156, respectively, thus forming the beads 81 and 82. The creasing edges 166 and 168 of the rollers 160 and 164 indent the flaps 38 and 40, respectively, producing the crease lines 83 and 84 (FIG. 12) therein adjacent the hinge lines thereof. However, since rolling contact rather than sliding contact occurs between the carton flaps and the creasing members of the squaring mechanism the friction forces tending to impede progress of the carton through the squaring mechanism are greatly reduced, and the likelihood that the carton might be crushed by the involved pusher block 22 is correspondingly reduced.

Whereas all illustrated forms of the carton squaring mechanism of the invention have been described herein as including two opposed squaring shoes that operate similarly and simultaneously upon opposite ends of a carton, it is to be understood that under some circumstances, only one end of a carton will be squared in accordance with the present invention, and that the other end can be closed and, if desired, squared by any suitable means. Under such circumstances, each carton will be presented to only one of the squaring shoes of the invention, and any desired form of guide can be provided for the other end of the carton to assure proper positioning of the end being squared with relation to the single squaring shoe.

While preferred embodiments of the mechanism of the present invention are described herein, it should be noted that various changes may be made therein without departing from the spirit of the invention as defined in the appended claims.

The invention having thus been described, What is claimed and desired to be secured by Letters Patent is:

1. Carton squaring apparatus comprising conveyor means for advancing a carton having spaced apart panels interconnected by a wall, and a shoe mounted in position for engagement by the carton during advancement of the carton by said conveyor means and including means for flexing the wall inward of the carton to concave form, means for creasing the carton along the lines of juncture of the wall with the panels to relieve strains in the carton.

and thereby set the wall in concave form, and means for maintaining the carton panels flat and undistorted during said creasing.

2. A carton squaring mechanism comprising a pair of opposed inwardly facing shoes each having a channelshaped cross section with a web portion and two spaced inwardly projecting flange portions, the distance between the flanges of each of said shoes being substantially the same as the height of the cartons to be squared, means for moving the cartons between the shoes with the end regions of each carton sliding through the opening between the flanges of said shoes, and means adjacent the juncture between the Web portion of each shoe and each of the flanges thereof for forming a reverse fold at the edges of the ends of said cartons and for forming reverse crease lines in each of the carton ends adjacent said edges.

3. A carton squaring mechanism comprising opposed spaced apart shoes of channel-shaped cross section, each shoe including a web portion and two spaced apart flanges projecting therefrom toward the other shoe, the distance between the flanges of each shoe being substantially equal to the height of a carton to be squared, and means for moving a carton between the shoes with the end regions of the carton sliding through the openings between the flanges of the shoes, the web portion of each of said shoes having therein crimping grooves adjacent the contiguous faces of the flanges of the shoe, the width of each of said crimping grooves being substantially equal to twice the thickness of the carton stock, the distance between the bottoms of corresponding crimping grooves of the opposed shoes being substantially equal to the length of each carton.

4. A carton squaring mechanism comprising opposed spaced apart shoes of channel-shaped cross section, each shoe including a web portion and two spaced apart flanges projecting therefrom toward the opposed shoe, the distance between the flanges of each shoe being substantially equal to the height of a carton to be squared, the web portion of each of said shoes having slots therein adjacent the flanges of the shoe, and a forming roller rotatably mounted in each of said slots with its outwardly facing end spaced from the carton engaging face of the adjacent flange a distance approximately equal to twice the thickness of the carton stock.

5. A carton squaring mechanism comprising a pair of opposed inwardly facing shoes each having a channelshaped cross section including a web portion and two spaced inwardly projecting flanges, the distance between the flanges of each of said shoes being substantially equal to the height of the cartons to be squared, means fixed to each of said shoes for heating the same, and means adjacent the juncture between the web portion of each shoe and each of the flanges thereof for forming a reverse fold at the edges of the ends of said cartons and for forming reverse crease lines in each of the carton ends adjacent said edges.

6. A carton squaring mechanism comprising two opposed spaced apart shoes of channel-shaped cross section, each shoe including a web portion and two spaced apart flanges projecting therefrom toward the other shoe, the distance between the flanges of each shoe being substantially equal to the height of a carton to be squared, means fixed to each of said shoes for heating the same, the web portion of each of said shoes having slots therein adjacent the flanges of the shoe, and a forming roller rotatably mounted in each of said slots with its outwardly facing end spaced from the carton engaging face of the adjacent flange a distance approximately equal to twice the thickness of the carton stock.

7. A carton squaring mechanism comprising opposed spaced apart shoes of channel-shaped cross section, each shoe including a web portion and spaced apart flanges projecting therefrom toward the other shoe, the distance between the flanges of each shoe being substantially equal to the height of a carton to be squared, means for moving the carton between the shoes with the ends of the carton sliding through the openings between the flanges of the shoes, means for heating said shoes, the web portion of each of said shoes having slots therein adjacent the flanges of the shoe, and a forming roller rotatably mounted in each of said slots with the outwardly facing end thereof spaced from the carton engaging face of the adjacent flange a distance approximately equal to twice the thickness of the carton stock.

8. A carton squaring mechanism comprising a shoe of channel-shaped cross section including a web portion and two spaced apart flanges projecting therefrom, the distance between said flanges being substantially equal to the height of a carton to be squared, the central portion of the inwardly facing surface of the web portion of said shoe having a plurality of longitudinally extending grooves therein, means for moving the end region of the carton between said flanges, and means adjacent the juncture between the web portion and each of the flanges of said shoe for forming a reverse fold at the edges of the end of said carton and for forming reverse crease lines in the carton end closely adjacent said edges.

9. A carton squaring mechanism comprising a shoe of channel-shaped cross section including a web portion and two spaced apart flange projecting therefrom, the distance between said flanges being substantially equal to the height of a carton to be squared, the central portion of the inwardly facing surface of the web portion of said shoe having a plurality of longitudinally extending grooves therein, means for moving the end of the carton between said flanges, means for pressing said end against said web portion while the end of the carton moves between the flanges, said web portion having narrow crimping grooves in the inner face thereof adjacent said flanges, the width of each of said grooves being substantially equal to twice the thickness of the material of which the carton is made.

10. A carton squaring mechanism comprising a shoe of channelshaped cross section including a web and two spaced apart flanges projecting therefrom, the distance between said flanges being substantially equal to the height of a carton to be squared, the central portion of the inwardly facing surface of the web of said shoe having a plurality of longitudinally extending grooves therein, means for moving the end region of the carton between said flanges in sliding engagement therewith and with the end of the carton in sliding pressure engagement with the web, said web having slots therein adjacent the flanges thereof, a crimping roller rotatably mounted in each of said slots with its outwardly facing end surface spaced from the carton engaging surface of the adjacent flange a distance approximately equal to twice the thickness of the carton stock.

11. A carton squaring mechanism comprising a shoe of channel-shaped cross section including a web portion and two spaced flanges projecting therefrom, the distance between said flanges being substantially equal to the height of a carton to be squared, the central portion of the inwardly facing vertical face of said shoe having a plurality of longitudinally extending grooves therein, means fixed to said shoe for heating the same, means for moving an end of the carton between said flanges, and means adjacent the juncture between the web portion and each of the flanges of said shoe for forming a reverse fold at the edges of the end of said carton and for forming a reverse crease line in the carton end closely adjacent each of said edges.

12. A carton squaring mechanism comprising a shoe of channel-shaped cross section including a web portion and two spaced flanges projecting therefrom, the distance between said flanges being substantially equal to the height of a carton to be squared, the central portion of the inwardly facing face of said shoe having a plurality of longitudinally extending grooves therein, means fixed to said shoe for heating the same, means for moving the end of the carton between said flanges, said web portions having crimping grooves in the inner face thereof adjacent the inner faces of said flanges, each of said grooves being adapted to receive a reverse fold of the carton stock therein and to crimp the fold to form a bead along an end wall of the carton as the carton is moved between the flanges.

13. A carton squaring mechanism comprising a shoe of channel-shaped cross section including a web portion and two spaced flanges projecting therefrom, the distance between said flanges being substantially equal to the height of a carton to be squared, means fixed to said shoe for heating the same, means for moving the end region of the carton between said flanges in sliding engagement therewith, said web portion having slots therein adjacent said flanges, and a crimping roller disposed in each of said slots with its outwardly facing end surface spaced from the carton engaging face of the adjacent flange a distance approximately equal to twice the thickness of the carton stock.

14. A carton squaring mechanism comprising a pair of opposed laterally spaced shoes each having a channelshaped cross section including a web portion and two spaced inwardly projecting flanges, said channels facing inwardly toward each other for receiving a carton, the distance between the flanges of each of said shoes being substantially equal to the height of the cartons to be squared, the central portion of the inner face of the web portion of each of said shoes having a plurality of longitudinally extending grooves therein, said web portions of the opposed shoes being spaced apart a distance less than the length of each of said cartons and having outwardly flared surfaces joining the central portions of said web portions with said flanges, and means for moving the cartons to he squared between said shoes with the ends of each carton sliding between the flanges of said shoes.

15. A carton squaring mechanism comprising opposed laterally spaced shoes each having a channel-shaped cross section including a web portion and spaced inwardly projecting flanges, said channels facing inwardly toward each other for receiving a carton, the distance between flanges of each of said shoes being substantially equal to one carton height, the central portion of the inner face of the web portion of each of said shoes having a plurality of longitudinally extending grooves therein, said web portions of the opposed shoes being spaced apart a distance less than one carton length and having outwardly flared surfaces joining the central portions of said web portions with said flanges, means fixed to each of said shoes for heating the same, and means for moving the cartons to be squared between said shoes with the ends of each carton sliding between the flanges of said shoes.

16. Apparatus for squaring opposed ends of a carton f the type having end walls joined by panels, said apparatus comprising a pair of shoes, means for moving the carton along said shoes, each shoe having a web portion for engaging an end wall of the carton, and flanges pro jecting generally perpendicularly from said web portion, the distance between said flanges being equal to the height of the carton so that said flanges overlie and slidingly engage the carton panels extending from the end walls of the carton, and a carton end wall receiving recess formed in and extending along each shoe at the juction of said flanges and said web portion, the web portions of said shoes being spaced apart a distance less than the width of the panels connecting the end walls to deflect the end walls into concave channels and bend the end Walls at said shoe recesses.

17. Apparatus for squaring opposed ends of a carton having end walls joined by panels, said apparatus comprising a pair of shoes, means for moving the carton along said shoes, each shoe having a web portion for engaging an end wall of the carton and flanges projecting generally perpendicularly from said Web portion, the distance between said flanges being equal to the height of the carton so that said flanges overlie and slidingly engage the carton panels extending from the end wall of the carton, and carton end wall receiving grooves formed in and extending along each shoe at the junction of said flanges and said web portion, said grooves being of a width for snugly receiving two thicknesses of the material of an end wall of the carton in response to inward deflection of the end Wall by a shoe web, the web portions of said shoes being spaced apart a distance less than the width of the panels connecting the end walls to deflect the end walls into concave channels and to crease the end walls into said shoe grooves.

18. Apparatus for squaring the end of a carton comprising a shoe for squaring the end of the carton, means for holding the end of the carton to be squared against said shoe, and means for moving the carton along said shoe, said shoe having a web portion for engaging the end wall of the carton to be squared and flanges projecting generally perpendicularly from said web portion, the distance between said flanges being equal to the height of the carton so that said flanges overlie and slidingly engage carton panels extending from the end of the carton to be squared, said shoe having narrow grooves formed therein extending along said shoe at the junction of said flanges and said web portion, said grooves being of a width for snugly receiving two thicknesses of the material of the end wall of the carton in response to inward deflection of the end wall of the carton by said shoe web portion.

19. A carton squaring shoe comprising a web for engaging a carton end wall and spaced apart flanges extending laterally and perpendicularly from said web for engaging panels connected to the carton end wall, said shoe being formed at the junctions of said web and flanges with longitudinally extending bead-forming grooves the outer walls of which are prolongations of the inner faces of said flanges so that the carton panels 10 remain flat as the carton is moved along the shoe, said flanges having free ends, the perpendicular spacing of the inner faces of said flanges being uniform along the entire lateral extent of the flanges out to their edges.

20. The method of squaring and channeling two ends of a carton having spaced apart flat panels joined by end walls connected thereto along fold lines, comprising the steps of sharply creasing opposed end walls of the carton at their junctions with the panels by bringing narrow portions of the end walls against the edges of the panels to form beads along the entire extent of the carton to thereby channel the two ends of the carton, While maintaining the panels at said junctions in their original flat condition during said creasing step, and simultaneously pressing the portions of the ends of the carton that are intermediate the beads inwardly toward each other.

21. Apparatus for increasing the crushing resistance of opposed end Walls of a car-ton of the type having end walls joined by panels, said apparatus comprising a pair of shoes, mean for moving the car-ton along said shoes, each shoe having a web portion for engaging an end wall of the carton and flanges projecting generally perpendicularly from said web portion, the distance be tween said flanges being equal to the height of the carton so that said flanges overlie and slidingly engage the edge portions of the carton panels, said shoes being laterally spaced by a distance such that the junctions of each web portion and an associated flange on one shoe are spaced from the corresponding junctions on the other shoe by a distance that is at least equal to the width of the carton panels so that the panels remain flat and undistorted as the cartons are moved along said shoes, said web portions being formed so that the web portions of one shoe intermediate its functions with the shoe flanges are spaced from the corresponding web portion of the other shoe a distance that is less than the width of the carton panels for deflecting the carton end walls toward each other, forming concave channels in the ends of the cartons as the cartons are moved along said shoes.

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